Impact of ruminant digestion on germination of native warm‐season grasses in the southeastern United States

Abstract

Abstract Many forage grasses increase seed dispersal by having their seeds ingested by grazing animals and later deposited elsewhere, reducing parent‐plant offspring competition and improving germination conditions. This study discusses the dissemination of seeds by livestock to spread desired plant species across grassland and pastures. The effects of rumen and intestinal digestion on seed germination of dormancy‐prone native warm‐season grasses were investigated to assess their potential for transporting valuable forage and biomass crops in the southeastern United States. Two experiments were performed using switchgrass (SG) ( Panicum virgatum L.) and big bluestem (BBS) ( Andropogon gerardii L.) to determine viability and germination post‐exposure to two subsequent stages of the ruminant digestive system. Stage I, rumen digestion, was performed in situ in a cannulated steer for 48 h, followed by Stage II: Small intestine digestion, simulated in vitro via abomasal digestion for 24 h. The results from this study revealed that the combination of both stages, rumen and small intestine digestion, resulted in the highest percentage of seed mortality in each species; however, for the seeds that did survive, they had a delayed germination by 7 days compared to the control. Average germination percentage was reduced by 87% in SG and 81% in BBS after exposure to both digestion stages. Results of this study have shown low grass seed germination rates following digestive‐tract exposure, suggesting that using grazing livestock as a management strategy to propagate BBS and SG is impractical and would significantly reduce viability and germination.